1. Field of Invention
The present invention relates to a method of shot peening metal parts, and also to a machine enabling such a method to be implemented.
2. Discussion of Related Art
The technique of shot peening metal parts is well known and consists in imparting compression stresses to the surface of the part by subjecting it to bombardment from projectiles constituted by balls or small shot.
The permanent stress induced on the part by such bombardment has the effect of opposing the appearance and the propagation of cracks, thereby improving the fatigue resistance of the treated part.
It is known that a part can be shot peened by projecting the projectiles towards the surface for treatment by means of a nozzle that is fed with compressed gas.
That technique poses at least two problems when applied to thin walls such as the blades of aeroengine turbines.
Firstly, blades must be treated simultaneously on both opposite faces in order to avoid any deformation that would lead to any perceptible modification of their shape.
Secondly, it is difficult or even impossible to engage the nozzle between the blades when they are close together.
Furthermore, it is difficult with that technique to control the intensity of shot peening with accuracy.